The numerical calculations were performed with the NRG Ljubljana [1]}, [2]} implementation of the numerical
renormalization group method [3]}, [4]} using
the separate conservation of the isospin (axial charge) in each channel \(\tau \) ,
as well as the conservation of the \(z\) -component of the total spin, i.e., \(SU(2) \times SU(2) \times U(1)\)  symmetry. The calculations for the Kondo model were performed with the discretization parameter
\(\Lambda =4\)  with the broadening parameter \(\alpha =0.8\)  for Figs. REF  and REF .
For Fig. REF  the values of \(\alpha \)  used were 0.1 for \(f \le 0.1\) ,
0.2 for \(f=0.6\)  and 0.7, 0.4 for \(f=0.8\)  and 0.9 and 0.6 for \(f=1\) .
The calculations for the Anderson model have been performed using
\(\Lambda =3\)  with the broadening parameter \(\alpha =0.3\) .
We kept up to 10000 multiplets (or up to cutoff 10 in energy units) in the truncation,
averaging over \(N_z=4\)  different discretization meshes. The spectral functions were computed using
the complete Fock space algorithm [5]}, and the resolution for the Anderson model
was improved using the “self-energy trick” [6]}.
